91

Names of 91

• Cardinal: 91 can be written as Ninety-one.

Scientific notation

• Scientific notation: 9.1 × 10¹

Factors of 91

• Number of distinct prime factors ω(n): 2
• Total number of prime factors Ω(n): 2
• Sum of prime factors: 20

Divisors of 91

• Number of divisors d(n): 4
• Complete list of divisors:
  1 7 13 91
• Sum of all divisors σ(n): 112
• Sum of proper divisors (its aliquot sum) s(n): 21
• 91 is a deficient number, because the sum of its proper divisors (21) is less than itself. Its deficiency is 70

Bases of 91

• Binary: 1011011₂
• Hexadecimal: 0x5B
• Base-36: 2J

Squares and roots of 91

• 91 squared (91²) is 8281
• 91 cubed (91³) is 753571
• The square root of 91 is 9.5393920141
• The cube root of 91 is 4.4979414453

Scales and comparisons

• 91 seconds is equal to 1 minute, 31 seconds.
• To count from 1 to 91 would take you about forty-five seconds.

  This is a very rough estimate, based on a speaking rate of half a second every third order of magnitude. If you speak quickly, you could probably say any randomly-chosen number between one and a thousand in around half a second. Very big numbers obviously take longer to say, so we add half a second for every extra x1000. (We do not count involuntary pauses, bathroom breaks or the necessity of sleep in our calculation!)

• A cube with a volume of 91 cubic inches would be around 0.4 feet tall.

Recreational maths with 91

• 91 backwards is 19
• The number of decimal digits it has is: 2
• The sum of 91's digits is 10
• More coming soon!